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[en] In this paper production of bitumen adding elemental sulfur at oxidation of oil residue are investigated. The objects of research were distilled residue of Karazhanbas crude oil and elemental sulfur. These oil residue characterized by a low output of easy fractions and the high content of tar-asphaltene substances, therefore is the most comprehensible feedstock for producing bitumen. The sulfur is one of the oil product collected in oil extraction regions. Oxidation process of hydrocarbons carried out at temperatures from 180 up to 210 °С without addition of sulfur and with the addition of sulfur (5-10 wt. %) for 4 hours. At 200 °С oxidation of hydrocarbons with 5, 7 and 10 wt.% sulfur within 3-4 h allows receiving paving bitumen on the mark BND 200/300, BND 130/200, BN 90/130 and BN 70/30. Physical and mechanical characteristics of oxidation products with the addition of 5-7 wt. % sulfur corresponds to grade of paving bitumen BND 40/60. At the given temperature oxidized for 2.5-3 h, addition of 10 wt. % sulfur gave the products of oxidation describing on parameters of construction grades of bitumen (BN 90/10). (paper)
[en] Based on the results of studies dealing with the issue of waste disposal of drilling mud fluids including oil sludge, or oil with a focus on solidification method can be concluded that this method is developed at very good level from theoretical and practical aspects for the conditions of oil and gas industry. This is confirmed by results of performance-verification tests in terms of chemical formulas of individual additives and also in terms of functionality of solidification facility. These are characterized by a relatively simple construction and therefore by relatively low price. The fundamental problem is choosing the optimal recipe and - both in terms of claims for laboratory work, but mainly due to the specific need of each individual waste solution, or the sludge bed. The results confirm that verificated method of liquidation of waste liquids by solidification seems to be suitable for practical liquidation of drilling fluids containing higher concentrations of economically undesirable and unacceptable substances, particularly thermo-stable washes.
[en] Processes of sulphuric compounds transformation for petroleum and heavy residuals under radiation and thermal treatment action are studied. It is shown that sulphuric compounds are concentrated in heavy fractions as a result of radiation processing. Heavy petroleum products irradiation provokes considerable decrease in the content of mercaptans, disulphides and sulphides, which transfer to sulphoxides and sulphones appearing during radiation-induced oxidation process. (author)
[en] We consider the Hopfield-Potts model for the covariation between residues in protein families recently introduced in Cocco, Monasson, Weigt (2013). The patterns of the model are inferred from the data within a new gauge, more symmetric in the residues. We compute the statistical error bars on the pattern components. Results are illustrated on real data for a response regulator receiver domain (Pfam ID PF00072) family
[en] Ribonuclease P (RNase P) is a ribonucleoprotein that catalyzes the processing of 5′ leader sequences of precursor tRNAs (pre-tRNA). RNase P proteins PhoRpp21 and PhoRpp29 in the hyperthermophilic archaeon Pyrococcus horikoshii, homologs of human nuclear RNase P proteins Rpp21 and Rpp29 respectively, fold into a heterodimeric structure and synergistically function in the activation of the specificity domain (S-domain) in RNase P RNA (PhopRNA). To elucidate the molecular basis for their cooperativity, we first analyzed binding ability to PhopRNA using a pull-down assay. The result showed that PhoRpp21 is able to bind to PhopRNA in the absence of PhoRpp29, whereas PhoRpp29 alone has reduced affinity to PhopRNA, suggesting that PhoRpp21 primarily functions as a binding element for PhopRNA in the PhoRpp21-PhoRpp29 complex. Mutational analyses suggested that although individual positively charged clusters contribute little to the PhopRNA binding, Lys53, Lys54, and Lys56 at the N-terminal helix (α2) in PhoRpp21 and 10 C-terminal residues in PhoRpp29 are essential for PhopRNA activation. Moreover, deletion of a single stranded loop linking P11 and P12 helices in the PhopRNA S-domain impaired the PhoRpp21-PhoRpp29 complex binding to PhopRNA. Collectively, the present results suggest that PhoRpp21 binds the loop between P11 and P12 helices through overall positively charged clusters on the surface of the complex and serves as a scaffold for PhoRpp29 to optimize structural conformation of its N-terminal helix (α2) in PhoRpp21, as well as C-terminal residues in PhoRpp29, for RNase P activity. - Graphical abstract: A mechanistic model for the synergistic activation of PhopRNA by PhoRpp21 and PhoRpp29. PhoRpp21 binds to the loop between P11 and P12 helices in PhopRNA and serves as a scaffold for PhoRpp29 to optimize a structural conformation of a positively charged edge composed of lysine residues (●) at α2 in PhoRpp21and C-terminal residues (Ð“ÑžÐ²Ð‚“Ð²Ð‚№) in PhoRpp29 on the protein complex which probably stabilize stacking interactions between PhopRNA and pre-tRNA. ▲ indicates the processing site in pre-tRNA. Display Omitted - Highlights: • RNase P proteins PhoRpp21 and PhoRpp29 synergistically function in RNase P catalysis. • PhoRpp21 functions as an RNA-binding element in the PhoRpp21-PhoRpp29 complex. • PhoRpp21 serves as a scaffold for PhoRpp29 in RNase P. • PhoRpp21 binds the loop between P11 and P12 helices in the PhopRNA S-domain. • The molecular basis for the cooperativity of PhoRpp21 and PhoRpp29 is presented.
[en] This paper presents a review of work carried out to ascertain the residual stresses present within a T- plate section. The contour method, the incremental deep hole drilling (iDHD) and the incremental centre hole drilling (ICHD) are coupled to determined longitudinal and transverse components of residual stress in the weld tope of the fillet weld in the as-welded condition. This paper presents first the measurement using the iDHD method and the measurement obtained using the contour method is then presented. The accuracy and resolution of the contour method results are directly linked to the quality of the electro- discharge machining (EDM) cut made. The challenges incurs by cutting complex geometry like this T- plate section are identified and their influence on residual stresses calculated by the contour method is quantified. (author)
[en] A mechanical measuring method is presented for inexpensive measuring of internal stresses. The accuracy of the method is assessed by considering a number of errors and is checked by means of comparative measurements. The distributions of internal stresses in depth determined so far are physically plausible. (orig./HP)
[de]Zur kostenguenstigen Messung von Eigenspannungen wird ein mechanisches Messverfahren vorgestellt. Die Verfahrensgenauigkeit wird aufgrund einer Fehlerbetrachtung abgeschaetzt und mit Hilfe von vergleichenden Messungen ueberprueft. Die bisher ermittelten Eigenspannungs-Tiefenverteilungen sind physikalisch plausibel. (orig./HP)
[en] While defect assessment standards such as BS 7910 “Guide to methods of assessing the acceptability of flaws in metallic structures” present residual stress profiles for T butt welds in thick sections they inherently assume that the weld pass placement strategy is such that the last weld pass is always on the base plate. There is limited information on what the residual stress profiles are if alternative pass placement strategies are used in high strength weldments and structures. Similarly there is limited information on what are the residual stress profiles under the body of the weld and the superimposition on the balancing residual stresses in the base plate away from the weld on pre-existing residual stresses. This paper presents neutron strain scanning work on a high strength, curved base plate, double sided T Butt weld undertaken such that the pass placement in each layer progressed away from the base plate towards the abutting member to determine the potential of reduction in residual stresses at the base plate weld toes. Key results were validated by the Deep Hole Drilling Technique. The results obtained show that a major reduction in the magnitude of the residual stresses occurred at the weld toes of the base plate with a corresponding increase in the center of the weld. Weld toe through thickness profiles were reduced from those of BS 7910. Balancing residual stresses in the base plate were minimal. Discussion includes comparison to results obtained in similar test plates welded with a different pass placement strategy. (author)
[en] A method for evaluating residual stress using an instrumented indentation test was developed some decades ago. More recently, another method was developed, using a Knoop indenter. The conversion factor ratio, which is one of the key factors in the evaluation algorithm, has been taken to be 0.34, although this value comes from an experimental result and its physical meaning has not been examined. Here we examine the physical meaning of this conversion factor from the previous residual stress model, and calculate its ratio using analytical model of the stress field beneath the indenter. In this process, we assumed that the conversion factor ratio was the ratio of the projected area of the plastic zone generated during the Knoop indentation test. An analysis of the stress field beneath the indenter was performed by FE simulation. Actual nanoindentation was conducted after Knoop indentation testing, using the interface-bonding technique, to identify the plastic zone. In addition, the conversion factor ratio was also calculated for the case where residual stress was present, and the geometric ratio of the Knoop indenter was different. A comparison of our results with those from previous studies showed that the conversion factor ratio obtained using our assumption was in good agreement with previous studies.
[en] Antibiotics are used in food to: -therapy and prophylaxis, -increase the productivity of the food producing animals. The presence of antimicrobial residues: -constitutes a potential human health hazard. has significant impact on international food trade. has implications on technological process in dairy industry. Detection of antibiotic residues is of great interest. It helps protect humans against the effects of such residues, the more it can support the participation of our country in international trade. Charm II test is one of the methods of detection of antimicrobial residues. The tests utilize microbial or antibody receptor assay technology. The sample is incubated with a binding agent (microbial cells with specific receptor sites or with specific antibodies attached) and a tracer (the radio-labeled version of the antibiotic to be detected). The amount of tracer on the binding agent is measured using a scintillation counter and is compared to a pre-determined cut-off or control point. If contaminating antibiotic is present, it will prevent the binding of the tracer by occupying the receptors on the binding agent. The less labeled tracer detected, the more contaminating antibiotic there is present in the sample. This work, carried out at the Radiochemical Laboratory of the National Centre of Nuclear Science and Technology, has two parts: 1/ The first is reserved to a literature review provides an overview on antibiotics and the charm II method. 2/ The second is devoted to the experimental study and presentation of results.